( Reaffirmed 2005 )

MELAMINE FORMALDEHYDE RESINS TO IMPROVE WET STRENGTH OF PAPER SPECIFICATION

ICS

83.080.10

0 BIS 2000

pJREAUOFIND'LANSTANDARDS
Iy4ANAK BHAYAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI I10002
Fdnx/ar~ 2000

Price Group

3

Plastics Sectional Committee,

PCD 12

FOREWORD This Indian Standard was adopted by the Bureau of Indian Standards, after the draft finalized by the Plastics Sectional Committee, had been approved by the Petroleum, Coal and Related Products Division Council. Melamine formaldehyde resins are notable for their outstanding toughness, excellent mechanical strength, electrical insulating properties and water and chemical resistance. Because of these excellent properties, the resin is most suitable and used for imparting wet strength to the paper. For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS 2 : 1960 `Rules for rounding off numerical values (revised)`. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard.

IS 14752 : 2000

Indian Standard MELAMINE FORMALDEHYDE RESINS TO IMPROVE WET STRENGTH OF PAPER SPECIFICATION
1 SCOPE This standard prescribes the requirements and methods of sampling and test for melamine formaldehyde resin to improve wet strength of paper. 2 NORMATIVE REFERENCES 4.3 Properties Solution 4.3.1 Appearance Clear to slightly milky, free from dirt. 4.3.2 Stability The solution after storing at room temperature for 24 h exhibit a bluish opalescence and must not show any precipitation turbidity, gelation or curdling. 4.4 The resins complying with this specification shall also meet the characteristic requirements given in Table 1. Table 1 Requirement of Melamine Formaldehyde Resin for Wet Strength of Paper
SI No. (1)
i) ii) iii) iv) v)

of

Melamine

Formaldehyde

The following standards contain provisions which, through reference in this text, constitute provisions of this Indian Standard. At the time of publication, the All standards are editions indicated were valid. subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below: IS No. 460 (Part 1) : 1985 878 : 1975 1060 (Part 1) : 1966 2828 : 1964 4905 : 1968 3 TERMINOLOGY For the purpose of this standard, the definitions in IS 2828 and the following shall apply. 3.1 Wet Strength It shall mean the ratio of wet tensile strength to dry tensile strength expressed in percentage. 4 REQUIREMENTS 4.1 Description The resins shall be white, dry, finely divided powder which shall pass 95 percent through 150 pm IS sieve [see IS 460 (Part l)]. 4.2 Solubility Readily soluble in hydrochloric acid (HCl) normal solution at 40°C having pH around 0.1. given Title Specification for test sieves : Part 1 Wire cloth test sieve (third revision) Graduated measuring cylinders (first revision) Methods of sampling and test for paper and allied products, Part 1 (revised) Glossary of terms used in the plastics industry Methods for random sampling

Characteristics 0)
Moisture content, percent by mass, Mm

Requirement (3)
3

Method of Test (4)
Annex A Amex B Annex C Annex D

Bulk density, 8/l
Nitrogen content, percent by mass, Min lnsolublc content, percent, Mnx Wet strength retention, percent, MB?

4.50-650
37.5 1.5 2s

Annex E

5

PACING AND MARKING

5.1 Packing The material shall be packed in well closed containers or as agreed between the purchaser and the supplier. 5.2 Marking The containers shall be securely closed and legibly marked with the following informations:

a) Manufacturers
mark, if any;

name

and recognized

trade-

b) Name of the material;

c> Colour
4

of the material;

Net mass of the material in the container;

e) Month and year of manufacture; f) Batch No. or code No.; 8) Shelf life of the material: and

IS 14752 : 2000 h) Informations on the following lines shall be given either on the container or through leaflet. "The preparation of resin solution, recommended type of mixing, apparatus and necessary precautions, of any kind shall be stated". Marking or known to consist of different batches of manufacture the batches shall be marked separately and the group of containers in each shall constitute separate lot. 6.2.1.1 Number of samples

5.3 BIS Certification The container Mark.

may also be marked with the Standard

53.1 The use of the Standard Mark is governed by the provisions of the Bureau of Indian Standards Act, 1986 and the Rules and Regulations made thereunder. The details of conditions under which the licence for the use of Standard Mark may be granted to manufacturers or produces may be obtained from the Bureau of Indian Standards. 6 SAMPLING CONFORMITY 6.1 General In drawing, preparing, storing and handling the following precautions and directions observed: samples, shall be AND CRITERIA FOR

For ascertaining the conformity of the material in a lot to the requirements of the specification, tests shall be carried out on each lot separately. The number (n) of containers to be selected from the lot shall depend on the size of lot (N) and shall be in accordance with Table 2. Table 2 Scale of Sampling
Lot Size fN! No. of Containers to be Selected in a Sample (12) 5 7 9 11 13 15

Upto

100

101 " 150 151 " 200 201 " 300 301 " 400 401 and above

a> Samples
cl

shall not be taken in an exposed place.

b) The sampling

instrument shall be made of stainless steel and shall be clean and dry. Precautions shall be taken to protect the samples, the material being sampled, the sampling instrument and the containers for sample from adventitious contamination. Samples shall be placed in suitable, clean, dry, air-tight metal, glass or polythene containers on which the material has RO action. the temperature of the material does not vary unduly from the room temperature (cool, dry and away from the sun).

6.213 Each container in the sample shall be selected at random from each lot. For this purpose reference may be made to IS 4905. 6.3 Number of Tests From each container selected in the sample the materials shall be tested for the various requirements given at 4. 6.4 Criteria for Conformity

4

e) Samples shall be stored in such a manner that

6.2

Scale of Sampling The lot shall be declared as conforming to the requirements of the specification, it' the requirements for various characteristics as given at 4 are satisfied.

6.2.1 Lot All the containers in a single consignment of the material drawn from a single batch of manufacture shall constitute a lot. If the consignment is declared

2

IS 14752 : 2000

ANNEX A
[Table I, SZ No. (i)]
DETERMINATION A-l GENERAL by Dean and Stark OF MOISTURE CONTENT

A-3 REAGENTS A-3.1 Chromic Acid Cleaning Solution solvents may be used: with a boiling range of

The moisture content is determined method. A-2 APPARATUS A-2.1 Distillation Flask

A-3.2 One of the following a) b) c) Petroleum naphtha 90 to 210°C; n-Heptane Toluene -

boiling point around 98'C; and boiling point around I IO'C.

Made of hard glass with 500 ml capacity and provided with a ground-glass socket. A-2.2 Reflux Condenser

A-4 PROCEDURE Clean the entire apparatus (see Fig. 1) with a chromic acid solution to minimize the adherence of water droplets to the sides of the condenser and the receiver. Rinse thoroughly with distilled water and dry completely before using. Place an appropriate amount of the sample accurately weighed into the distilkttion tlask. The amount of sample taken shal1 be such that the distillation tlask is not more than one-third full; if shall nat contain more than 1.8 ml of water. Add sufficient volume of the solvent (100 to 200 ml) so that the sample shall be completely covered by the solvent while the distillation is in progress. Swirl to mix and add pumice stone to ensure steady boiling. Assemble the apparatus and fill the receiver with the solvent by pouring the solvent through the condenser until it begins to overflow into the distillation flask. Attach a guard tube containing anhydrous calcium chloride at the top of the condenser to prevent condensation of atmospheric moisture within the tube. In order that the refluxing may be under control, wrap the distillation flask and the tube leading to the receiver with asbestos fibre. Heat the flask at such a rate that about lOOdrops are distilled over, increase the distillation rate to about 200 drops/min and continue heating until no more water is collected. Purge the condenser occasionally during the distillation with 5-ml portions of the solvent in order to wash down any moisture odhcring to the walls of the condenser. The water in the trap may hc made to separate from the solvent by means of a copper wire, one end of which is twisted into a helix. The copper wire if moved up and down in the condenser and receiver occasionally causes the water the settle down at the bottom of the trap. Reflux until the water level in the receiver remains unchanged t'o~ 30 min and then shut elf the source of heat. Flush the condenser with the solvent, making use of the copper wire to disengage any moisture droplets. Allow to stand for about IS min and then read the volume ol` water.

Made of glass, water cooled, having the outside diameter of the inner tube 16 to 17 mm, and that of the jacket 23 to 25 mm. The lower end of the condenser is provided with a ground-glass cone. The tip of the condenser is ground at an angle of approximately 30' from the vertical axis. A-2.3 Receiver (or Trap)

Made of hard glass and consisting essentially of an upper chamber, provided with a side-arm leading `to the distillation flask, and a cylindrical graduated portion, the lowest end of which is sealed. The opening of the upper chamber is provided with a ground-glass socket fitting the cone of the condenser. The lower end of the side-arm is provided with a ground-glass cone fitting the socket of the distillation flask. The graduated portion has a capacity of 5 ml when filled to the highest graduation mark. The scale covers the range 0 to 5 ml, with graduation marks at 0. I ml, intervals. The error at any indicated capacity shall not exceed 0.02 ml. A-2.4 Heat Source

Either an oil-bath or an electric heater provided with a sliding rheostat or other means of heat control. The temperature of the oil in the bath shall not be very much higher than the boiling point of petroleum naptha (see A-3.2). A-2.5 Copper Wire

Long enough to extend through the condenser with one end twisted into a spiral. The diameter of the spiral shall be such that it fits snugly within the graduated portion of receiver and yet can be moved up and down.

3

IS 11752 : 2000

9.5

TO 12.7

OD

! I1 I I f I

I 1 I ' 1

-

.2 TO 24 ID

Alldimensions

in millimetres.

FIG. 1 MOISTURE DGTILLATION APPARATUS A-5 CALCULATION 100 v Moisture content, percent by mass = 7 where
V =

A-6 PRECISION The results of a duplicate determination of moisture content of the material, percent by mass, shall not vary by more than -t 0.05 from that of the first determination.

volume in ml of water collected, and

h/l

= mass in g ol` the material taken for the test.

IS 14752 : 2000

ANNEX B [Table 1, Sl No. (ii)]
DETERMINATION OF BULK DENSITY B-l APPARATUS B-l.1 Graduated Cylinder
of 100 ml capacity (see IS 878) with internal diameter of 27 to 29 mm. B-l.2 without tapping, and level the powder with the minimum of disturbance. Leave the cylinder untouched for 5 min and add more powder if necessary, to bring the contents to the IO&ml mark, level again with the minimum of disturbance. Weigh the filled cylinder. B-3 CALCULATION Bulk density, g/l = Mass of material (in g) x 10 Volume occupied by the material _

Funnel

Wide and short-stemmed. B-2 PROCEDURE

B-2.1 Rest the funnel over the top edge of the tared graduated cylinder. Fill the cylinder ;o the lOO-ml mark by pouring the material through the funnel,

ANNEX C [Table 1, SZNo. (iii)]
DETERMINATION OF NITROGEN CONTENT

C-l GENERAL
The nitrogen method. content is determined by Kjeldhals

C-2 PROCEDURE Weigh a sample containing 0.15-0.25 g, of nitrogen into an 800 ml Kjeldhal flask. Add OS-O.75 g of mercury (or 0.5-0.8 _g of mercuric oxide), 10 g of potassium sulphate and very cautiously 25-35 ml of concentrated sulphuric acid, mix well. Digest the mixture slowly until frothing ceases, then boil briskly until 2 h after the solution becomes clear. Allow to cool, add 500 ml of water slowly with constant swirling, a few anti-bump particles. Prepare a mixture of 25-30 ml of sodium thiosulphate solution (80 g of Na&03.5H20 per litre of solution) and 80-90 ml of 50 percent of NaOH; pour the mixture slowly down the neck of the flask so that it straitifies on the bottom and connect the flask immediately to the distillation system through division scrubber. Mix the contents of the flask well and distill about 300 ml over into 50 ml

of 0.5 N hydrochloric or sulphuric acid containing methyl red or methyl purple indicator having adjusted the delivery tube below the surface of the acid before starting the distillation step. Titrate the excess acid with standard 0.5 N sodium hydroxide. Carry a blank on the reagents through the sample procedure. C-3 CALCULATION Nitrogen content, percent by mass = (B - A) ' N ' 1*40L W where A B N w = standard NaOH solution to titrate sample, ml; = standard NaOH solution ml; to titrate blank,

= normality of standard NaOH solution; and = weight of sample in g.

IS 14752 : 2000

ANNEX D [Table 1, SZNo. (iv)]
DETERMINATION OF INSOLUBLE CONTENT D-l PREPARATION OF MELAMINE FORMALDEHYDE SOLUTION
acid by mixing distilled water and concentrated hydrochloric acid (specific gravity 1.18) in the ratio of 212 parts distilled water and 8.5 parts concehtrated hydrochloric acid (v/v). Take out 192 ml of the diluted acid and maintaining its temperature at 40 f 2°C by a thermostatic water bath, dissolve accurately weighed 25.0 g melamine formaldehyde powder by adding small quantities and stirring continuously to get uniform solution. pre-weighed 40 No. Whatman filter paper. Wash the residue with hot distilled water till it is free from soluble chloride ions and dry to constant mass at 105 to 1 loOC D-3 CALCULATION Insoluble where m = mass in g of the residue, and iOOm content, percent = 7

D-l.1 Dilute hydrochloric

D-2 PROCEDURE
Filter the solution prepared at D-l.1 through a

M = mass in g of the sampIe taken for the test.

ANNEX E [Table 1, SE No. (v)]
DERTERMINATION OF WET STRENGTH RETENTION E-l OUTLINE OF THE METHOD
The wet strength retention of paper is the ratio-of wet tensile strength to dry tensile strength expressed in percentage. The tensile strenph shall be determined on a standard sheet of 8 m (gsm) paper made by standard pulp evaluation method (containing 2 percent melamine formaldehyde on oven dry basis) after drying the sheets at room temperature for 24 h. E-2 PRINCIPLE Wet strength retention in terms of percedt by mass is determined when 2 percent melamine formaldehyde resin by mass (in the form prepared solution) is added to paper stock of pH 5.5. E-3 PREPARATION OF MELAMINE MALDEHYDE SOLUTION FOR STRENGTH _FORWET

E-4.2 Maintain the pH of the pulp stock 5.0 to 5.5.
E-4.3 Add.the appropriate volume of solution in the pulp stock so as to maintain its quantity 2 percent on oven dry basis pulp stock as well as melamine resin in the pulp. E-4.4 Stir the pulp under mechanical stirrer for 20 min. Keep the pulp stock for 1 h then prepare 10 hand made sheets. E-4.5 Dry the sheets on hand sheet rings at standard conditions for 24 h. E-4.6 Determine the dry tensile strength [see 12.3 of IS 1060 (Part I)] taking 15 mm wide strips from the hand made sheets (10 strips). E-4.7 For accelerated ageing keep the other IO strips (2nd set) in the oven maintained at 105 f 5OC for 4 h. E-4.8 Soak the strips for 2 h in water after accelerated ageing and again determine tensile strength of wet strips after blotting their extra water.
NOTE The tensile tester shall be levelled and the jaws movement shall be set 95 mmlmin.

Prepare solution as descriked in D-l. Keep this solution undisturbed at room temperature for 24 h for maturation. Observe the solution after 24 h for its appearance and stability requirements and the solution conforming to the requirements (see Table 1) shall be used for the determination of wet strength retention. E-4 PROCEDURE E-4.1 Determine the consistency (oven dried fibrous matter percent) of the pulp stock.

E-5 CALCULATION Wet strength retention, percent Average of wet tensile strength x loo = Average of dry tensile strength

Bureau of Indian Standards BIS is a statutory institution established under the Bureau harmonious development of the activities of standardization, and attending to connected matters in the country. Copyright BIS has the copyright of all its publications. No part of these publications may be reproduced in any form without the prior permission in writing of BIS. This does not preclude the free use, in the course of implementing the standard, of necessary details, such as symbols and sizes, type or grade designations. Enquiries relating to copyright be addressed to the Director (Publications), BIS. Review of Indian Standards Amendments are issued to standards as the need arises on the basis periodically; a standard along with amendments is reaffirmed when needed; if the review indicates that changes are needed, it is taken should ascertain that they are in possession of the latest amendments `BIS Handbook' and `Standards: Monthly Additions'. This Indian Standard has been developed of comments. Standards are also reviewed such review indicates that no changes are up for revision. Users of Indian Standards or edition by referring to the latest issue of
oflndian Standards Act, 1986

marking

and quality

certification

to promote of goods

.. from Dot : No. PCD 12 ( 1475 ). I Issued Since Publication Date of Issue Text Affected

Amendments Amend No.

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